1. Field of the Invention
This invention relates to a firearm comprising a housing, a barrel extending in a first direction, a chamber structure, a trigger and firing means, wherein the chamber structure is constituted by a chamber member, which is separate from the barrel and is movable in the housing in a second direction, which is transverse to the barrel axis, and an actuating mechanism is provided for reciprocating said chamber member in said second direction between a firing position and a loading position, the actuating mechanism comprises a slider, which is movable in said first direction from an initial position to a stand-by position, said slider is adapted to be releasably locked in either of its said positions and comprises a cam opening, which has a cam face that extends over the width that is traversed by the chamber member, and cooperates with an actuating pin, which is coupled to the chamber member for a movement in said second direction and extends in a third direction, which is transverse to said first and second directions.
2. Description of the Prior Art
Firearms in which the chamber is defined by a separate chamber member, which is movable between a firing position, in which a round is discharged, and a loading position, in which a cartridge is received by the chamber member, permit the firing means to be simplified and permit the firearm to be designed with a smaller overall length. In the prior art the actuating mechanism for reciprocating the chamber member between its loading and firing positions comprises linkages and as is apparent from Austrian Patent Specification No. 26,115, French Patent Specification No. 317,851 and U.S. Pat. No. 658,010 the chamber member is reciprocated between its loading and firing positions by means of toggle joints, swivel arms or rocker arms. But such linkages are rather liable to be deranged and are designed only for manual actuation. Besides, the linkages involve a high structural expenditure and do not permit a keeping of the chamber members in defined positions and the space required by the linkage often results in an obstruction of the loading and ejecting operations.
U.S. Pat. No. 3,667,147 discloses a firearm having a slider which is provided with a cam slot for cooperating with an actuating pin, which is coupled to the chamber member and extends into the cam opening. The S-shaped cam slot effects a positive control of the chamber member during its upward and downward movements. This may give rise to disturbances and the elongate cam slot requires the slider to be displaced over a long distance so that a considerable overall dimension is required. Besides, the positive control of the upward movement of the chamber member to its firing position prolongs the time required for the movement of the chamber member so that the rate of rapid fire is restricted.